Preheat the oven to 170°C/fan 150°C/gas mark 3 ​

Make the pastry: rub in the gluten-free flour and butter to until it resembles fine breadcrumbs. Then add and mix in the caster sugar. Beat the egg in a separate jug. Gradually add the egg into the flour and butter mix. With your hand bring together the pastry into a ball. Flatten into a disc, cover with cling film and chill for about 1 hour.

Roll out the pastry onto a lightly (gluten-free) floured surface to about 3mm thickness. Carefully place your pastry into your tray. I use a 23 x 33cm (9 x 13-inch) tray for this recipe. Spread the jam in an even layer over the base of the pastry case.

Pre-heat the oven to 180°C/fan 160°C/gas mark 4.

Sponge filling: place the butter and sugar into a bowl and beat together (using an electric whisk) until pale and fluffy. Begin to add the eggs, one at a time whisking in between each egg. Add the vanilla extract and fold in the gluten-free self-raising flour. Spoon the mixture over the jam and level it out with the back of a spoon.

Place on the middle shelf of the oven for 30–35 minutes, or until the filling is golden on top and feels firm in the middle. If the tart seems to be browning too quickly, cover with a sheet of foil. If your oven is uneven, turn once during cooking.

Allow to cool, dust with icing sugar and serve with pouring cream, custard or simply on its own.